/*

 * Copyright (c) 2014-2020 Pavel Kalvoda <me@pavelkalvoda.com>

 *

 * libcbor is free software; you can redistribute it and/or modify

 * it under the terms of the MIT license. See LICENSE for details.

 */

#ifndef LIBCBOR_COMMON_H

#define LIBCBOR_COMMON_H

#include <assert.h>

#include <stdbool.h>

#include <stddef.h>

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include "cbor/cbor_export.h"

#include "cbor/configuration.h"

#include "data.h"

#ifdef __cplusplus

extern "C" {

/**

 * C99 is not a subset of C++ -- 'restrict' qualifier is not a part of the

 * language. This is a workaround to keep it in C headers -- compilers allow

 * linking non-restrict signatures with restrict implementations.

 *

 * If you know a nicer way, please do let me know.

 */

#define CBOR_RESTRICT_POINTER

#else

// MSVC + C++ workaround

#define CBOR_RESTRICT_POINTER CBOR_RESTRICT_SPECIFIER

#endif

static const uint8_t cbor_major_version = CBOR_MAJOR_VERSION;

static const uint8_t cbor_minor_version = CBOR_MINOR_VERSION;

static const uint8_t cbor_patch_version = CBOR_PATCH_VERSION;

#define CBOR_VERSION               \

  _CBOR_TO_STR(CBOR_MAJOR_VERSION) \

  "." _CBOR_TO_STR(CBOR_MINOR_VERSION) "." _CBOR_TO_STR(CBOR_PATCH_VERSION)

#define CBOR_HEX_VERSION \

  ((CBOR_MAJOR_VERSION << 16) | (CBOR_MINOR_VERSION << 8) | CBOR_PATCH_VERSION)

/* http://stackoverflow.com/questions/1644868/c-define-macro-for-debug-printing

 */

#ifdef DEBUG

#include <stdio.h>

#define _cbor_debug_print(fmt, ...)                                     \

  do {                                                                  \

    if (DEBUG)                                                          \

      fprintf(stderr, "%s:%d:%s(): " fmt, __FILE__, __LINE__, __func__, \

              __VA_ARGS__);                                             \

  } while (0)

extern bool _cbor_enable_assert;

// Like `assert`, but can be dynamically disabled in tests to allow testing

// invalid behaviors.

#define CBOR_ASSERT(e) assert(!_cbor_enable_assert || (e))

#define _CBOR_TEST_DISABLE_ASSERT(block) \

  do {                                   \

    _cbor_enable_assert = false;         \

    block _cbor_enable_assert = true;    \

  } while (0)

#else

#define debug_print(fmt, ...) \

  do {                        \

  } while (0)

#define CBOR_ASSERT(e)

#define _CBOR_TEST_DISABLE_ASSERT(block) \

  do {                                   \

    block                                \

  } while (0)

#endif

#define CBOR_ASSERT_VALID_TYPE(item_type) \

  CBOR_ASSERT(item_type >= CBOR_TYPE_UINT && item_type <= CBOR_TYPE_FLOAT_CTRL);

#define _CBOR_TO_STR_(x) #x

#define _CBOR_TO_STR(x) _CBOR_TO_STR_(x) /* enables proper double expansion */

#ifdef CBOR_HAS_NODISCARD_ATTRIBUTE

#define CBOR_NODISCARD [[nodiscard]]

#else

#define CBOR_NODISCARD

#endif

#ifdef __GNUC__

#define _CBOR_UNUSED __attribute__((__unused__))

// Fall back to __attribute__((warn_unused_result)) if we don't have

// [[nodiscard]]

#ifdef CBOR_HAS_NODISCARD_ATTRIBUTE

#define _CBOR_NODISCARD CBOR_NODISCARD

#else

#define _CBOR_NODISCARD __attribute__((warn_unused_result))

#endif

#elif defined(_MSC_VER)

#define _CBOR_UNUSED __pragma(warning(suppress : 4100 4101))

#define _CBOR_NODISCARD

#else

#define _CBOR_UNUSED

#define _CBOR_NODISCARD

#endif

#ifdef CBOR_HAS_BUILTIN_UNREACHABLE

#define _CBOR_UNREACHABLE __builtin_unreachable()

#else

#define _CBOR_UNREACHABLE

#endif

typedef void* (*_cbor_malloc_t)(size_t);

typedef void* (*_cbor_realloc_t)(void*, size_t);

typedef void (*_cbor_free_t)(void*);

CBOR_EXPORT extern _cbor_malloc_t _cbor_malloc;

CBOR_EXPORT extern _cbor_realloc_t _cbor_realloc;

CBOR_EXPORT extern _cbor_free_t _cbor_free;

// Macro to short-circuit builder functions when memory allocation fails

#define _CBOR_NOTNULL(cbor_item) \

  do {                           \

    if (cbor_item == NULL) {     \

      return NULL;               \

    }                            \

  } while (0)

// Macro to short-circuit builders when memory allocation of nested data

// fails

#define _CBOR_DEPENDENT_NOTNULL(cbor_item, pointer) \

  do {                                              \

    if (pointer == NULL) {                          \

      _cbor_free(cbor_item);                        \

      return NULL;                                  \

    }                                               \

  } while (0)

/** Sets the memory management routines to use.

 *

 * By default, libcbor will use the standard library `malloc`, `realloc`,

 * and `free`.

 *

 * A custom allocator is the intended mechanism for limiting memory

 * consumption when parsing untrusted CBOR data. Because definite-length

 * collections pre-allocate storage sized by the declared element count,

 * a crafted input can request a very large allocation before any element

 * data is read. A capping `custom_malloc` that returns NULL above a chosen

 * threshold will cause `cbor_load` to return `CBOR_ERR_MEMERROR` instead of

 * attempting the allocation. See `examples/capped_alloc.c` for a

 * self-contained demonstration.

 *

 * \rst

 * .. warning::

 *   This function modifies the global state and should

 *   therefore be used accordingly. Changing the memory handlers while

 *   allocated items exist will result in a ``free``/``malloc`` mismatch.

 *   This function is not thread safe with respect to both itself and all

 *   the other *libcbor* functions that work with the heap.

 *

 * .. note::

 *   `realloc` implementation must correctly support `NULL`

 *   reallocation (see e.g. http://en.cppreference.com/w/c/memory/realloc)

 *

 * .. note::

 *   `free` implementation must accept `NULL` as a no-op (as the standard

 *   `free` does). libcbor does not allocate storage for empty items and

 *   will pass their `NULL` data pointer to `free` when they are deallocated.

 *

 * \endrst

 *

 * @param custom_malloc malloc implementation

 * @param custom_realloc realloc implementation

 * @param custom_free free implementation

 */

CBOR_EXPORT void cbor_set_allocs(_cbor_malloc_t custom_malloc,

                                 _cbor_realloc_t custom_realloc,

                                 _cbor_free_t custom_free);

/*

 * ============================================================================

 * Type manipulation

 * ============================================================================

 */

/** Get the type of the item

 *

 * @param item

 * @return The type

 */

_CBOR_NODISCARD

CBOR_EXPORT cbor_type cbor_typeof(

    const cbor_item_t* item); /* Will be inlined iff link-time opt is enabled */

/* Standard CBOR Major item types */

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item an #CBOR_TYPE_UINT?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_uint(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item a #CBOR_TYPE_NEGINT?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_negint(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item a #CBOR_TYPE_BYTESTRING?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_bytestring(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item a #CBOR_TYPE_STRING?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_string(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item an #CBOR_TYPE_ARRAY?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_array(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item a #CBOR_TYPE_MAP?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_map(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item a #CBOR_TYPE_TAG?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_tag(const cbor_item_t* item);

/** Does the item have the appropriate major type?

 * @param item the item

 * @return Is the item a #CBOR_TYPE_FLOAT_CTRL?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_isa_float_ctrl(const cbor_item_t* item);

/* Practical types with respect to their semantics (but not tag values) */

/** Is the item an integer, either positive or negative?

 * @param item the item

 * @return  Is the item an integer, either positive or negative?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_is_int(const cbor_item_t* item);

/** Is the item an a floating point number?

 * @param item the item

 * @return  Is the item a floating point number?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_is_float(const cbor_item_t* item);

/** Is the item an a boolean?

 * @param item the item

 * @return  Is the item a boolean?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_is_bool(const cbor_item_t* item);

/** Does this item represent `null`

 *

 * \rst

 * .. warning::

 *   This is in no way related to the value of the pointer.

 *   Passing a null pointer will most likely result in a crash.

 * \endrst

 *

 * @param item the item

 * @return  Is the item (CBOR logical) null?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_is_null(const cbor_item_t* item);

/** Does this item represent `undefined`

 *

 * \rst

 * .. warning::

 *   Care must be taken to distinguish nulls and undefined values in C.

 * \endrst

 *

 * @param item the item

 * @return Is the item (CBOR logical) undefined?

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_is_undef(const cbor_item_t* item);

/*

 * ============================================================================

 * Memory management

 * ============================================================================

 */

/** Increases the item's reference count by one

 *

 * Constant complexity; items referring to this one or items being

 * referred to are not updated.

 *

 * This function can be used to extend reference counting to client code.

 *

 * Defined `static inline` so the single-instruction increment is emitted

 * directly at the call site — meaningful for hot loops that build

 * #cbor_item_t trees, where every constructed item touches the refcount.

 *

 * @param item Reference to an item

 * @return The input \p item

 */

static inline cbor_item_t* cbor_incref(cbor_item_t* item) {

  item->refcount++;

  return item;

}

/** Slow path of #cbor_decref: performs the actual deallocation once the

 * reference count reaches zero. Do not call directly; use #cbor_decref.

 *

 * Split from #cbor_decref so the fast path (decrement + zero check) can

 * inline while the recursive free logic — which dominates code size —

 * stays out of line.

 */

CBOR_EXPORT void _cbor_decref_free(cbor_item_t* item);

/** Decreases the item's reference count by one, deallocating the item if

 * needed

 *

 * In case the item is deallocated, the reference count of all items this

 * item references will also be #cbor_decref 'ed recursively.

 *

 * The fast path (decrement, check for zero) is `static inline`; only the

 * uncommon deallocation branch calls into #_cbor_decref_free. This keeps

 * every non-final decref a couple of instructions at the call site.

 *

 * @param item_ref Reference to an item. Will be set to `NULL` if deallocated

 */

static inline void cbor_decref(cbor_item_t** item_ref) {

  cbor_item_t* item = *item_ref;

  CBOR_ASSERT(item->refcount > 0);

  if (--item->refcount == 0) {

    _cbor_decref_free(item);

    *item_ref = NULL;

  }

}

/** Decreases the item's reference count by one, deallocating the item if

 * needed

 *

 * Convenience wrapper for #cbor_decref when its set-to-null behavior is

 * not needed

 *

 * @param item Reference to an item

 */

CBOR_EXPORT void cbor_intermediate_decref(cbor_item_t* item);

/** Get the item's reference count

 *

 * \rst

 * .. warning::

 *   This does *not* account for transitive references.

 * \endrst

 *

 * @todo Add some inline examples for reference counting

 *

 * @param item the item

 * @return the reference count

 */

_CBOR_NODISCARD

CBOR_EXPORT size_t cbor_refcount(const cbor_item_t* item);

/** Provides CPP-like move construct

 *

 * Decreases the reference count by one, but does not deallocate the item

 * even if its refcount reaches zero. This is useful for passing

 * intermediate values to functions that increase reference count. Should

 * only be used with functions that `incref` their arguments.

 *

 * \rst

 * .. warning::

 *   If the item is moved without correctly increasing the

 *   reference count afterwards, the memory will be leaked.

 * \endrst

 *

 * @param item Reference to an item

 * @return the item with reference count decreased by one

 */

_CBOR_NODISCARD

CBOR_EXPORT cbor_item_t* cbor_move(cbor_item_t* item);

/** Compares two items for structural (encoding-level) equality

 *

 * Two items are structurally equal when they would produce identical bytes

 * if serialized by a correct CBOR encoder that preserves the in-memory

 * representation. Every aspect of the encoding counts:

 *

 * - **Major type**: `CBOR_TYPE_UINT` and `CBOR_TYPE_NEGINT` are distinct even

 *   if the argument bytes happen to be the same.

 * - **Integer encoding width**: `cbor_build_uint8(1)` and

 * `cbor_build_uint16(1)` are *not* structurally equal, even though both

 * represent the integer 1. Use the integer value accessors (`cbor_get_uint64`

 * etc.) if you need value-level comparison.

 * - **Definite vs. indefinite length**: a definite-length array and an

 *   indefinite-length array with the same elements are *not* structurally

 * equal.

 * - **Chunk boundaries**: two indefinite bytestrings or strings that carry the

 *   same bytes but split them across a different number of chunks are *not*

 *   structurally equal.

 * - **Map entry order**: maps are compared positionally — entry at index i in

 *   \p item1 must match entry at index i in \p item2. Maps that carry the same

 *   key-value pairs in a different order are *not* structurally equal. (CBOR

 *   maps are unordered in the data model; for data-model equality see RFC 8949

 *   §5.6.1.)

 * - **Float encoding width**: `cbor_build_float2(1.5)` and

 *   `cbor_build_float4(1.5)` are *not* structurally equal.

 * - **NaN payload**: floating-point NaN values with different bit patterns are

 *   *not* structurally equal.

 * - **Tag number**: tags with different tag numbers are *not* structurally

 * equal.

 *

 * Runs in time linear in the encoded byte size of the items and performs no

 * additional memory allocations.

 *

 * \rst

 * .. note::

 *   This function implements *structural* equality, not the data-model equality

 *   defined by RFC 8949. In the CBOR data model, encoding width is invisible

 *   and maps are unordered sets of key-value pairs. If you need data-model

 *   equality (e.g., ``uint8(1) == uint64(1)``), you must implement it on top

 *   of this library.

 * \endrst

 *

 * Neither \p item1 nor \p item2 may be `NULL`. Passing `NULL` is a

 * programming error and will trigger an assertion failure in debug builds.

 *

 * @param item1 First item; must not be `NULL`

 * @param item2 Second item; must not be `NULL`

 * @return `true` if \p item1 and \p item2 are structurally equal

 */

_CBOR_NODISCARD

CBOR_EXPORT bool cbor_structurally_equal(const cbor_item_t* item1,

                                         const cbor_item_t* item2);

#ifdef __cplusplus

}

#endif

#endif  // LIBCBOR_COMMON_H